If you have received your Notice of Assessment and you think it is incorrect or you have additional information to provide the CRA, here are some points to consider so you can determine the best course of action to take. · If you want to provide the CRA with missing information for a tax return you have filed previously: You can generally ask for a change to your personal tax return for a tax year ending in any of the 10 previous calendar years. So you can ask for a change rather than filing an objection right away. · If you...

If you have received your Notice of Assessment and disagree with it, you have the right to object.
You can start by filing an objection with the CRA. Filing an objection is the first step in the formal process of resolving a dispute.
For individuals, you can file an objection whichever of the following two dates is later: - One year after the date of the return’s filing deadline or - 90 days after the day the CRA sent the Notice of Assessment.
If you are unable to file within the time limit mentioned above because of circumstances beyond your control,...

Have you received your Notice of Assessment already from the CRA? If you do not agree with the CRA’s assessment of your tax return and think they have misinterpreted the facts or applied the law incorrectly, you can object to your tax assessment.
It is your right to object to income tax assessments and reassessments and determinations and re-determinations such as the goods and services tax / harmonized sales tax (GST / HST) credit, the Canada child tax benefit and the disability tax credit.
The first step would be to call the CRA and see if that can resolve the issue...